Furniture component with hardened exposed surfaces



NOV. 15, 1949 c, LUNDSTROM 2,488,301

FURNITURE COMPONENT WITH HARDENED EXPOSED SURFACES Filed April 17, 1944 Fic5.2

Fial

3nnentor Carl Bryh'olf Lundsl-rom (Ittornegs Patented Nov. 15, 1949 UNITED STATES PATENT OFFICE FURNI'TUIEE wrrn nARnEfiEi) EXPOSED SURFACES I Carl Bryii'olf Lundstrom,"Little' FallsyN. "Y. A'pmieetibn Apr'ii 17, 1944, Serial Nei'51;432

"a claims:

This invention relates to wooden furniture comporients and particularly that partoi' these components subjected to excessive wear or surface injury. I v v p Typical examples are the exposed corners of center posts or the'leg's of desks, exposed edges of the writing bed'or' top of desks, arms or front edges of chairs and the like which are continually subjected to exce sive wear or impact, caiusing rupture offthe' surface, often to the extent of s'pli'nterihg the wood itself. Theses'urfacesf when so ruptured often cause annoying damage] or injury to the person or the a'pparel of the user.

The invention provides a componenthavingfan exposed surface or corner densified. Fromjthe metho'ds'tand'point the invention contemplates giving this particular part its desired form or shape by compressionof the" outer fibers by the' use of forming dies To permit this compression it is necessary to start with a; blank'which is oversize to the extent of the relative compression that will take place during the shaping and densifying cycle;

This compression is actually accomplished by first plasticizing the section to be compressed, causing the lignin to release its grip on the cellulose fibres. The preferred mode of pie-e ticing the invention is; therefore, to s'tart with the component part; ovr s'ize in cross s'ect ion, and then to plasticize to a moderate depth below the'surfaceof the area to be densified, by the application of heat.- The surface to be densified may be impregnated in advance with a resin forming compound that will act as a plasticizing agent when heat is applied. 'Howver, the natural moisture contained inr'nost w'oods will, if properly controlled, serve as'this plasticizing agent. The application-of heat tojthe area to' be densified will causethe'soitehing of thewood at this point. p 'Ihe'blanlg inthi's condition is then 'compressedto its final shape-orform by the application of pressure" through forming dies. The further application of'heat' is continud'ar'i'd' as the critical temperature is reached, thermosetting takes place and the component will retain its; cha'r'1ged shape perm-"an By proper choice or dies, a finarsnio'otn surface isihip'arted to the component in which the grain of the wood has not been changed in appearance.

In this way the component is given a dense splinter-proof integral case or shell which matches other wooden parts, and can be stained or varnished or otherwise treated as desired.

Practical embodiments of the invention as applied to a desk leg or center post will now be 2 described by reference to the accompanying drawing. In the drawing: 7 p v i g igure l is a diagrammatic end View of the oversize leg blank impregnated and associated with dies prior to pressing Figure 2 is a similar iew show i'ngith e condif tions at the completion of the pressingoperation. Figure 3 is a fragmentaryperspective" of the finished article, v I v J Figure fl! is a view similar to Figure 2'suggs't ing'adifferent conf guration. Y I Figure 5 is a View sif ar' toFigure 1' showing w veneer m be' l l Y i. l v n i 6 is' a view similarto Figure 2 showing conditions after completion ofipressing' with the p i a v nee a Fisi efi; w i i f 7 is ad e 'mmat c' n View i a n the l e sv icon an d mees pn whi h oebur in connection with. the treatment and ai'ticle illustratedin Figures 1 2, and 3. I v F ure c an o e 'ws ay at li e esk isind qat'ed a? H A b a k IQ ih jw i i die qd eu beaten A7? to are: in c sh transs v mi flie theflfin h de l le $51 n ed t be. il es id men i n erers e t v le ause he: ame nt e, mpres n de ends eve h d t o tr atm n ndpth s fe fie sity- Ap r mete p n0r O ssi Qiteb1e, q I. .1$ =es are indicated'inFigure (where the dotted'lins e ent bri i ia out ne I e wane Whi the contour-of the final article after densification is indicatedjin full lines. v v g Asabovesuggested it isjn-ot always necessary to impregnate the wood with a resin forming om un in ch. a 'Q PW' i s et t depth of impregnation would be approximately that indicated in Figure" 1 by the shaded area [2, Impreg nation can be effec'ted in various known ways, the simplest being a soaking operationfor a. suitable period 'Ihose wood's which will deo' a m iee P c b91 14. W ut. imp n bll61 9 9 3219 1 10 1s ,ute' o ir t n d th is Us al a h in istu .cqil ento x th pre o a qn' s r ac can hepreheatd to a moderate iitent'befof 'intot heated forming die M to be densified rests.

w In the example illustrated in Figures 1 and 2 the forming die I4 has a filleted corner I5 designed to compress the corner I6 of the blank into a rounded surface which iseven more dense than the adjacent surfaces because of the extra condensation of the wood 3 which there occurs. If the blank is not preheated the pressure is applied slowly so that the heat from the forming die will be transferred to the blank before heavy pressure occurs. If the blank has been preheated the pressure can be applied somewhat more rapidly.

The form assumed at the completion of the pressing operation is indicated in Figure 2. When the resin sets, the blank retains its compressed form and the densified surface is finished so far as form and surface are concerned. The completed leg or corner post is indicated in Figure 3. In this figure, l1 and I 8 represent densified surfaces which meet in the even more markedly densified corner 19.

In Figure 4 a somewhat different contour is suggested, the purpose being to indicate, as is shown at 2|, the possibility of producing molded sections having reentrant angles and even sharp protruding corners.

A significant thing about the procedure is the fact of surface densification and the fact that the wood article is changed to a different final form by a pressing operation whichproduces this final form and which creates the final surface texture. If not impregnated with a resin forming substance or if impregnated with a suitable resin forming substance such as urea combined with methylolurea, a wooden article so treated will take stain and can be varnished or otherwise treated. After such treatment it matches untreated portions of'the wood, that is portions which have not been densified, and this fact is of the utmost importance in furniture which, to use a-boat-builders term, is finished bright.

If it is desired to apply veneers, this is possible according to procedure indicated in Figures 5 and 6. In these Figures the blank is indicated at 22 in Figure 5 and is impregnated with any suitable plastic which will function as a glue. Many such are available. The veneer '23, which may, if desired also be impregnated with a similar plastic, is assembled with the blank in the die as shown inFigure 5. When subjected to pressure, the parts assume the form shown in Figure 6, and if the lower die is properly heated, the veneer will be bonded to the blank, and the veneer and also a, portion of the surface of the blank will be densified as already suggested. As indicated in Figures 5 and 6 the veneer is slightly over-size until after the completion of the pressing operation whereupon the excess is trimmed away. In applying veneer as above described it is convenient to preheat the blank to which the veneer is applied so that it will be comparatively soft.

While several embodiments have been described in some detail, these are examples and do not limit the scope of the invention which can be variously applied to various different furniture components. The form of the die to be used is subject to considerable variation. Any die and press which will develop the. necessarypressure and permit the necessary application of heat concurrently with pressure, may be substituted. Different woods will require to' be treated in slightly different ways, but ,these'involve matters of detail, the general principle of the invention being applicable as described.

What is claimed is:

1. A wooden furniture component comprising a straight strip with the grain thereof running longitudinally, said strip having an exposed rounded corner and a flat side tangent thereto, both corner and side being transversely condensed and densified to extend a distance beneath the surface thereof without material change in the externalshape or the appearance of the grain, the densifying of the corner portion being greater and extending deeper than that of the side, the fibers of the densified portions being permanently bonded in such state, and'the body of the strip being free from densification.

2. A wooden furniture component comprising a strip with the grain thereof running longitudinally, said strip having an exposed rounded corner and a fiat side tangent thereto, both corner and side being transversely condensed and densified to eXtend a distance beneath the surface'thereof without material change in the appearance of the grain, the densifying of the corner portion being greater and extending deeper than that of the side, the fibers of the densified portions being permanently bonded in such state and the body of the strip being free from densification.

3. A wooden furniture component comprising a strip with the grain thereof running longitudinally, said strip having an exposed corner and at least one adjacent face densified, said corner being more markedly densified than said face, the densification being evidenced by compression in a direction transverse to the grain of the wood, the fiber of the wood being bonded in such compressed state, the body and the remaining surface of the component being substantially free from densification.

CARL BRYNOLF LUNDSTROM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 28,309 Shaw May 15, 1860 207,721 Dougherty Sept. 3, 1878 453,384 Parker June 2, 1891 646,547 Sears Apr. 3, 1900 773,854 Dittmar et al. Nov. 1, 1904 838,391 Dittmar Dec. 11, 1906 1,068,775 Hyatt July 29, 1913 1,628,886 Jackson et al. May 17, 1927 1,697,616 Smith Jan 1, 1929 1,952,664 Esselen Mar. 27, 1934 1,981,567 Olsen Nov. 20, 1934 2,178,940 Rhodes Nov. 7, 1939 2,182,951 Sweetland Dec. 12, 1939 2,313,953 Loughborough Mar. 16, 1943 2,362,269 Hall Nov. 7, 1944 2,370,033 Hall Feb. 20, 1945 FOREIGN PATENTS Number Country Date 593,332 France Aug, 20, 1925 

